1. Field of the Invention
This invention relates to a multiband infrared imaging device of the thermal pulse gated image intensifier type, where thermal radiation from an object scene is focused onto a quantum ferroelectric detector, which radiation causes a temperature rise and generates signal electrons, which are pulled away from the detector by an electric field, and accelerated onto a phosphor display surface of an image intensifier to produce a visible image.
2. Description of the Prior Art
It is known in the art to use a pulse gated image intensifier to provide enhanced images. Such image intensifiers have been around quite some time. These image intensifiers use the photo-emissive effect to transfer photon energy to electrons, where this energy is sufficient to allow the electrons to jump over the photo cathode's potential barrier. An electric field is used to accelerate the photoelectrons. Over the years, intensifier devices had problems due to unwanted points on the photocathode or solid-state device components. These points can become charged and cause “hot spots” on the resulting display.
The quantum ferroelectric detector (QFE) of the invention uses the original problems of intensifier dielecic barrier discharge in a controlled way. Instead of using the photo emissive effect to generate electrons, the QFE uses the pyroelectric effect to generate electrons. An electrode with a point captures the pyroelectric electrons. The electrons distribute themselves over the entire electrode to form an equi-potential surface. The electron extension point has more charge than the rest of the electrode. The electrons are on the surface of the electrode, or two atomic diameters below the surface. These electrons can be pulled away from the surface by an electric field. The surface charge density lowers the potential barrier, which allows the surface charge to be pulled away. The charged extension points replaces the photo emissive effect as the mechanism to free an electron from a surface. The multiband infrared detector device (MIRID) amplifies the pyroelectric current from each QFE detector point or element by using an electric field to accelerate the signal and noise electrons across a gap, after which they strike a phosphor screen. The phosphor screen converts the energy of the electrons into visible photons. The brightness of this screen in turn may be additionally amplified by a one stage Gen II intensifier to increase the brightness to any range of eye comfort.